1/* $NetBSD: pwcache.c,v 1.35 2024/05/12 10:58:58 rillig Exp $ */ 2 3/*- 4 * Copyright (c) 1992 Keith Muller. 5 * Copyright (c) 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Keith Muller of the University of California, San Diego. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36/*- 37 * Copyright (c) 2002 The NetBSD Foundation, Inc. 38 * All rights reserved. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 52 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 59 * POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62#if HAVE_NBTOOL_CONFIG_H 63#include "nbtool_config.h" 64/* 65 * XXX Undefine the renames of these functions so that we don't 66 * XXX rename the versions found in the host's <pwd.h> by mistake! 67 */ 68#undef group_from_gid 69#undef user_from_uid 70#endif 71 72#include <sys/cdefs.h> 73#if defined(LIBC_SCCS) && !defined(lint) 74#if 0 75static char sccsid[] = "@(#)cache.c 8.1 (Berkeley) 5/31/93"; 76#else 77__RCSID("$NetBSD: pwcache.c,v 1.35 2024/05/12 10:58:58 rillig Exp $"); 78#endif 79#endif /* LIBC_SCCS and not lint */ 80 81#include "namespace.h" 82 83#include <sys/types.h> 84#include <sys/param.h> 85 86#include <assert.h> 87#include <grp.h> 88#include <pwd.h> 89#include <stdio.h> 90#include <stdlib.h> 91#include <string.h> 92#include <unistd.h> 93 94#if HAVE_NBTOOL_CONFIG_H 95/* XXX Now, re-apply the renaming that we undid above. */ 96#define group_from_gid __nbcompat_group_from_gid 97#define user_from_uid __nbcompat_user_from_uid 98#endif 99 100#ifdef __weak_alias 101__weak_alias(user_from_uid,_user_from_uid) 102__weak_alias(group_from_gid,_group_from_gid) 103__weak_alias(pwcache_groupdb,_pwcache_groupdb) 104#endif 105 106#if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_H 107#include "pwcache.h" 108 109/* 110 * routines that control user, group, uid and gid caches (for the archive 111 * member print routine). 112 * IMPORTANT: 113 * these routines cache BOTH hits and misses, a major performance improvement 114 */ 115 116/* 117 * function pointers to various name lookup routines. 118 * these may be changed as necessary. 119 */ 120static int (*_pwcache_setgroupent)(int) = setgroupent; 121static void (*_pwcache_endgrent)(void) = endgrent; 122static struct group * (*_pwcache_getgrnam)(const char *) = getgrnam; 123static struct group * (*_pwcache_getgrgid)(gid_t) = getgrgid; 124static int (*_pwcache_setpassent)(int) = setpassent; 125static void (*_pwcache_endpwent)(void) = endpwent; 126static struct passwd * (*_pwcache_getpwnam)(const char *) = getpwnam; 127static struct passwd * (*_pwcache_getpwuid)(uid_t) = getpwuid; 128 129/* 130 * internal state 131 */ 132static int pwopn; /* is password file open */ 133static int gropn; /* is group file open */ 134static UIDC **uidtb; /* uid to name cache */ 135static GIDC **gidtb; /* gid to name cache */ 136static UIDC **usrtb; /* user name to uid cache */ 137static GIDC **grptb; /* group name to gid cache */ 138 139static int uidtb_fail; /* uidtb_start() failed ? */ 140static int gidtb_fail; /* gidtb_start() failed ? */ 141static int usrtb_fail; /* usrtb_start() failed ? */ 142static int grptb_fail; /* grptb_start() failed ? */ 143 144 145static u_int st_hash(const char *, size_t, int); 146static int uidtb_start(void); 147static int gidtb_start(void); 148static int usrtb_start(void); 149static int grptb_start(void); 150 151 152static u_int 153st_hash(const char *name, size_t len, int tabsz) 154{ 155 u_int key = 0; 156 157 _DIAGASSERT(name != NULL); 158 159 while (len--) { 160 key += *name++; 161 key = (key << 8) | (key >> 24); 162 } 163 164 return (key % tabsz); 165} 166 167/* 168 * uidtb_start 169 * creates an empty uidtb 170 * Return: 171 * 0 if ok, -1 otherwise 172 */ 173static int 174uidtb_start(void) 175{ 176 177 if (uidtb != NULL) 178 return (0); 179 if (uidtb_fail) 180 return (-1); 181 if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) { 182 ++uidtb_fail; 183 return (-1); 184 } 185 return (0); 186} 187 188/* 189 * gidtb_start 190 * creates an empty gidtb 191 * Return: 192 * 0 if ok, -1 otherwise 193 */ 194static int 195gidtb_start(void) 196{ 197 198 if (gidtb != NULL) 199 return (0); 200 if (gidtb_fail) 201 return (-1); 202 if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) { 203 ++gidtb_fail; 204 return (-1); 205 } 206 return (0); 207} 208 209/* 210 * usrtb_start 211 * creates an empty usrtb 212 * Return: 213 * 0 if ok, -1 otherwise 214 */ 215static int 216usrtb_start(void) 217{ 218 219 if (usrtb != NULL) 220 return (0); 221 if (usrtb_fail) 222 return (-1); 223 if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) { 224 ++usrtb_fail; 225 return (-1); 226 } 227 return (0); 228} 229 230/* 231 * grptb_start 232 * creates an empty grptb 233 * Return: 234 * 0 if ok, -1 otherwise 235 */ 236static int 237grptb_start(void) 238{ 239 240 if (grptb != NULL) 241 return (0); 242 if (grptb_fail) 243 return (-1); 244 if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) { 245 ++grptb_fail; 246 return (-1); 247 } 248 return (0); 249} 250 251/* 252 * user_from_uid() 253 * caches the name (if any) for the uid. If noname clear, we always 254 * return the stored name (if valid or invalid match). 255 * We use a simple hash table. 256 * Return 257 * Pointer to stored name (or a empty string) 258 */ 259const char * 260user_from_uid(uid_t uid, int noname) 261{ 262 struct passwd *pw; 263 UIDC *ptr, **pptr; 264 265 if ((uidtb == NULL) && (uidtb_start() < 0)) 266 return (NULL); 267 268 /* 269 * see if we have this uid cached 270 */ 271 pptr = uidtb + (uid % UID_SZ); 272 ptr = *pptr; 273 274 if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) { 275 /* 276 * have an entry for this uid 277 */ 278 if (!noname || (ptr->valid == VALID)) 279 return (ptr->name); 280 return (NULL); 281 } 282 283 /* 284 * No entry for this uid, we will add it 285 */ 286 if (!pwopn) { 287 if (_pwcache_setpassent != NULL) 288 (*_pwcache_setpassent)(1); 289 ++pwopn; 290 } 291 292 if (ptr == NULL) 293 *pptr = ptr = (UIDC *)malloc(sizeof(UIDC)); 294 295 if ((pw = (*_pwcache_getpwuid)(uid)) == NULL) { 296 /* 297 * no match for this uid in the local password file 298 * a string that is the uid in numeric format 299 */ 300 if (ptr == NULL) 301 return (NULL); 302 ptr->uid = uid; 303 (void)snprintf(ptr->name, UNMLEN, "%lu", (long) uid); 304 ptr->valid = INVALID; 305 if (noname) 306 return (NULL); 307 } else { 308 /* 309 * there is an entry for this uid in the password file 310 */ 311 if (ptr == NULL) 312 return (pw->pw_name); 313 ptr->uid = uid; 314 (void)strlcpy(ptr->name, pw->pw_name, UNMLEN); 315 ptr->valid = VALID; 316 } 317 return (ptr->name); 318} 319 320/* 321 * group_from_gid() 322 * caches the name (if any) for the gid. If noname clear, we always 323 * return the stored name (if valid or invalid match). 324 * We use a simple hash table. 325 * Return 326 * Pointer to stored name (or a empty string) 327 */ 328const char * 329group_from_gid(gid_t gid, int noname) 330{ 331 struct group *gr; 332 GIDC *ptr, **pptr; 333 334 if ((gidtb == NULL) && (gidtb_start() < 0)) 335 return (NULL); 336 337 /* 338 * see if we have this gid cached 339 */ 340 pptr = gidtb + (gid % GID_SZ); 341 ptr = *pptr; 342 343 if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) { 344 /* 345 * have an entry for this gid 346 */ 347 if (!noname || (ptr->valid == VALID)) 348 return (ptr->name); 349 return (NULL); 350 } 351 352 /* 353 * No entry for this gid, we will add it 354 */ 355 if (!gropn) { 356 if (_pwcache_setgroupent != NULL) 357 (*_pwcache_setgroupent)(1); 358 ++gropn; 359 } 360 361 if (ptr == NULL) 362 *pptr = ptr = (GIDC *)malloc(sizeof(GIDC)); 363 364 if ((gr = (*_pwcache_getgrgid)(gid)) == NULL) { 365 /* 366 * no match for this gid in the local group file, put in 367 * a string that is the gid in numeric format 368 */ 369 if (ptr == NULL) 370 return (NULL); 371 ptr->gid = gid; 372 (void)snprintf(ptr->name, GNMLEN, "%lu", (long) gid); 373 ptr->valid = INVALID; 374 if (noname) 375 return (NULL); 376 } else { 377 /* 378 * there is an entry for this group in the group file 379 */ 380 if (ptr == NULL) 381 return (gr->gr_name); 382 ptr->gid = gid; 383 (void)strlcpy(ptr->name, gr->gr_name, GNMLEN); 384 ptr->valid = VALID; 385 } 386 return (ptr->name); 387} 388 389/* 390 * uid_from_user() 391 * caches the uid for a given user name. We use a simple hash table. 392 * Return 393 * the uid (if any) for a user name, or a -1 if no match can be found 394 */ 395int 396uid_from_user(const char *name, uid_t *uid) 397{ 398 struct passwd *pw; 399 UIDC *ptr, **pptr; 400 size_t namelen; 401 402 /* 403 * return -1 for mangled names 404 */ 405 if (name == NULL || ((namelen = strlen(name)) == 0)) 406 return (-1); 407 if ((usrtb == NULL) && (usrtb_start() < 0)) 408 return (-1); 409 410 /* 411 * look up in hash table, if found and valid return the uid, 412 * if found and invalid, return a -1 413 */ 414 pptr = usrtb + st_hash(name, namelen, UNM_SZ); 415 ptr = *pptr; 416 417 if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) { 418 if (ptr->valid == INVALID) 419 return (-1); 420 *uid = ptr->uid; 421 return (0); 422 } 423 424 if (!pwopn) { 425 if (_pwcache_setpassent != NULL) 426 (*_pwcache_setpassent)(1); 427 ++pwopn; 428 } 429 430 if (ptr == NULL) 431 *pptr = ptr = (UIDC *)malloc(sizeof(UIDC)); 432 433 /* 434 * no match, look it up, if no match store it as an invalid entry, 435 * or store the matching uid 436 */ 437 if (ptr == NULL) { 438 if ((pw = (*_pwcache_getpwnam)(name)) == NULL) 439 return (-1); 440 *uid = pw->pw_uid; 441 return (0); 442 } 443 (void)strlcpy(ptr->name, name, UNMLEN); 444 if ((pw = (*_pwcache_getpwnam)(name)) == NULL) { 445 ptr->valid = INVALID; 446 return (-1); 447 } 448 ptr->valid = VALID; 449 *uid = ptr->uid = pw->pw_uid; 450 return (0); 451} 452 453/* 454 * gid_from_group() 455 * caches the gid for a given group name. We use a simple hash table. 456 * Return 457 * the gid (if any) for a group name, or a -1 if no match can be found 458 */ 459int 460gid_from_group(const char *name, gid_t *gid) 461{ 462 struct group *gr; 463 GIDC *ptr, **pptr; 464 size_t namelen; 465 466 /* 467 * return -1 for mangled names 468 */ 469 if (name == NULL || ((namelen = strlen(name)) == 0)) 470 return (-1); 471 if ((grptb == NULL) && (grptb_start() < 0)) 472 return (-1); 473 474 /* 475 * look up in hash table, if found and valid return the uid, 476 * if found and invalid, return a -1 477 */ 478 pptr = grptb + st_hash(name, namelen, GID_SZ); 479 ptr = *pptr; 480 481 if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) { 482 if (ptr->valid == INVALID) 483 return (-1); 484 *gid = ptr->gid; 485 return (0); 486 } 487 488 if (!gropn) { 489 if (_pwcache_setgroupent != NULL) 490 (*_pwcache_setgroupent)(1); 491 ++gropn; 492 } 493 494 if (ptr == NULL) 495 *pptr = ptr = (GIDC *)malloc(sizeof(GIDC)); 496 497 /* 498 * no match, look it up, if no match store it as an invalid entry, 499 * or store the matching gid 500 */ 501 if (ptr == NULL) { 502 if ((gr = (*_pwcache_getgrnam)(name)) == NULL) 503 return (-1); 504 *gid = gr->gr_gid; 505 return (0); 506 } 507 508 (void)strlcpy(ptr->name, name, GNMLEN); 509 if ((gr = (*_pwcache_getgrnam)(name)) == NULL) { 510 ptr->valid = INVALID; 511 return (-1); 512 } 513 ptr->valid = VALID; 514 *gid = ptr->gid = gr->gr_gid; 515 return (0); 516} 517 518#define FLUSHTB(arr, len, fail) \ 519 do { \ 520 if (arr != NULL) { \ 521 for (i = 0; i < len; i++) \ 522 if (arr[i] != NULL) \ 523 free(arr[i]); \ 524 arr = NULL; \ 525 } \ 526 fail = 0; \ 527 } while (0) 528 529int 530pwcache_userdb( 531 int (*a_setpassent)(int), 532 void (*a_endpwent)(void), 533 struct passwd * (*a_getpwnam)(const char *), 534 struct passwd * (*a_getpwuid)(uid_t)) 535{ 536 int i; 537 538 /* a_setpassent and a_endpwent may be NULL */ 539 if (a_getpwnam == NULL || a_getpwuid == NULL) 540 return (-1); 541 542 if (_pwcache_endpwent != NULL) 543 (*_pwcache_endpwent)(); 544 FLUSHTB(uidtb, UID_SZ, uidtb_fail); 545 FLUSHTB(usrtb, UNM_SZ, usrtb_fail); 546 pwopn = 0; 547 _pwcache_setpassent = a_setpassent; 548 _pwcache_endpwent = a_endpwent; 549 _pwcache_getpwnam = a_getpwnam; 550 _pwcache_getpwuid = a_getpwuid; 551 552 return (0); 553} 554 555int 556pwcache_groupdb( 557 int (*a_setgroupent)(int), 558 void (*a_endgrent)(void), 559 struct group * (*a_getgrnam)(const char *), 560 struct group * (*a_getgrgid)(gid_t)) 561{ 562 int i; 563 564 /* a_setgroupent and a_endgrent may be NULL */ 565 if (a_getgrnam == NULL || a_getgrgid == NULL) 566 return (-1); 567 568 if (_pwcache_endgrent != NULL) 569 (*_pwcache_endgrent)(); 570 FLUSHTB(gidtb, GID_SZ, gidtb_fail); 571 FLUSHTB(grptb, GNM_SZ, grptb_fail); 572 gropn = 0; 573 _pwcache_setgroupent = a_setgroupent; 574 _pwcache_endgrent = a_endgrent; 575 _pwcache_getgrnam = a_getgrnam; 576 _pwcache_getgrgid = a_getgrgid; 577 578 return (0); 579} 580 581 582#ifdef TEST_PWCACHE 583 584struct passwd * 585test_getpwnam(const char *name) 586{ 587 static struct passwd foo; 588 589 memset(&foo, 0, sizeof(foo)); 590 if (strcmp(name, "toor") == 0) { 591 foo.pw_uid = 666; 592 return &foo; 593 } 594 return (getpwnam(name)); 595} 596 597int 598main(int argc, char *argv[]) 599{ 600 uid_t u; 601 int r, i; 602 603 printf("pass 1 (default userdb)\n"); 604 for (i = 1; i < argc; i++) { 605 printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n", 606 i, pwopn, usrtb_fail, usrtb); 607 r = uid_from_user(argv[i], &u); 608 if (r == -1) 609 printf(" uid_from_user %s: failed\n", argv[i]); 610 else 611 printf(" uid_from_user %s: %d\n", argv[i], u); 612 } 613 printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n", 614 pwopn, usrtb_fail, usrtb); 615 616 puts(""); 617 printf("pass 2 (replacement userdb)\n"); 618 printf("pwcache_userdb returned %d\n", 619 pwcache_userdb(setpassent, test_getpwnam, getpwuid)); 620 printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb); 621 622 for (i = 1; i < argc; i++) { 623 printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n", 624 i, pwopn, usrtb_fail, usrtb); 625 u = -1; 626 r = uid_from_user(argv[i], &u); 627 if (r == -1) 628 printf(" uid_from_user %s: failed\n", argv[i]); 629 else 630 printf(" uid_from_user %s: %d\n", argv[i], u); 631 } 632 printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n", 633 pwopn, usrtb_fail, usrtb); 634 635 puts(""); 636 printf("pass 3 (null pointers)\n"); 637 printf("pwcache_userdb returned %d\n", 638 pwcache_userdb(NULL, NULL, NULL)); 639 640 return (0); 641} 642#endif /* TEST_PWCACHE */ 643#endif /* !HAVE_PWCACHE_USERDB */ 644